Never complain and never explain.
Wherever you are - be all there.
Go for it now. The future is promised to no one.
If you're going through hell, keep going.
To be a good loser is to learn how to win.
Begin to be now what you will be hereafter.
You never know what motivates you.
Be gentle to all and stern with yourself.
If you've got a talent, protect it.
Either you run the day or the day runs you.
I have taught history on the high school and college levels, and am or have been a lecturer at the Smithsonian, The National Institutes of Health, and numerous colleges and universities, mostly on science fiction and technology subjects.